A lot of our trains have GPS which recognises where the train is and allows it to open the doors at the station, depending on the length of the train and the length of the platform. Doors can be opened manually in an emergency but we would not recommend it at other times.

What kind over crazy, overcomplicated world have we built for ourselves when trains need to send and receive signals from outer space in order to open a few doors? And does it work the other way round? Was the Beagle 2 Mars mission lost thanks to a problem with the electronic reservation system on the 08:15 to East Grinstead? Questions must be asked. If only a dodgy satnav had caused today's disruption in north London; we could have dusted off the old 'Euston, we have a problem' headline.